Group expression intensity estimation in videos via Gaussian Processes

Facial expression analysis has been a very active field of research in recent years. This paper proposes a method for finding the apex of an expression, e.g. happiness, in a video containing a group of people based on expression intensity estimation. The proposed method is directly applied to video summarisation based on group happiness and timestamps; further, a novel Gaussian Process Regression based expression intensity estimation method is described. To demonstrate its performance, experiments on smile intensity estimation are performed and compared to other regression based techniques. The smile intensity estimator is extended to group happiness intensity estimation. The proposed intensity estimator can be extended easily for other expressions. The experiments are performed on an `in the wild' dataset. Quantitative results are presented for comparison of our happiness-intensity detector. A user study was also conducted to verify the results of the proposed method.